Era
20th century
77
19th century
58
21st century
46
1900-1999
31
2000-2099
27
To 1500
16
1800-1899
13
18th century
10
1800-1999
9
1901-1991
7
2000-
7
Since 2000
5
1865-1918
4
1945-
4
1960-
4
Roman period, 55 B.C.-449 A.D.
4
1900-2099
3
2002-
3
16th century
2
1700-1799
2
1700-1899
2
1775-1865
2
1789-1900
2
17th century
2
1812-1870
2
1849-1914
2
1912-1945
2
1964-
2
1975-
2
1986-
2
2001-
2
Civil War, 1861-1865
2
Colonial period, ca. 1600-1775
2
Empire, 30 B.C.-284 A.D.
2
Since 1945
2
To 476
2
1039-1098
1
1066-1485
1
1500-1599
1
1540-1810
1
1700-1999
1
1727-1794
1
1743-1826
1
1760-1860
1
1762-1878
1
1775 - 1899
1
1775-1899
1
1800 - 1999
1
1822-
1
1865-1951
1
more ...